Low Intensity TMS Enhances Perception of Visual Stimuli
Low Intensity TMS Enhances Perception of Visual Stimuli
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DOI：
10.1016/j.brs.2015.06.012
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发表时间：
2015-11-01
影响因子：
7.7
通讯作者：
Harris, Justin A.
中科院分区：
文献类型：
--
作者：
Abrahamyan, Arman;Clifford, Colin W. G.;Harris, Justin A.
背景：经颅磁刺激（TMS）是认知和感觉神经科学中流行的功能绘图工具。虽然强 TMS 通常会降低表现，但最近的两项研究表明，传递到视觉皮层的弱 TMS 可以提高简单视觉任务的表现。这种改善被解释为视觉皮层中视觉诱发和 TMS 引发的神经元活动的总和，但这种相互作用的性质仍不清楚。 目的：本实验试图确定 TMS 的这些微弱脉冲是否有助于受试者看到视觉刺激本身，或创建可能无法识别为视觉刺激的独特“融合”感知。方法：我们测量了方向辨别任务中的对比度阈值，其中参与者报告倾斜光栅的方向（左或右）与垂直方向成 45 度。结果：弱 TMS 提高了识别光栅的灵敏度，这表明 TMS 与方向信息相加但保留了方向信息，以便受试者能够识别视觉刺激。我们使用大脑中感觉信号的非线性转导机制来解释这种效应。结论：低强度 TMS 增强神经信号同时保留刺激中编码的信息的能力可以作为一种新方法，通过选择性地将无意识刺激“推入”意识来研究意识的神经相关性。 (C) 2015 Elsevier Inc. 保留所有权利。
Background: Transcranial magnetic stimulation (TMS) is a popular functional mapping tool in cognitive and sensory neuroscience. While strong TMS typically degrades performance, two recent studies have demonstrated that weak TMS, delivered to visual cortex, can improve performance on simple visual tasks. The improvement was interpreted as the summation of visually-evoked and TMS-elicited neuronal activity in visual cortex, but the nature of this interaction remains unclear.Objective: The present experiments sought to determine whether these weak pulses of TMS assist subjects to see the visual stimulus itself or create a distinct "melded" percept that may not be recognizable as the visual stimulus.Methods: We measured contrast thresholds in an orientation discrimination task in which participants reported the orientation (left or right) of gratings tilted 45 degrees from vertical.Results: Weak TMS improved sensitivity for identifying gratings, suggesting that TMS sums with but preserves orientation information so that the subject can recognize the visual stimulus. We explain the effect using a mechanism of non-linear transduction of sensory signals in the brain.Conclusions: The capability of low-intensity TMS to augment the neural signal while preserving information encoded in the stimulus can be employed as a novel approach to study the neural correlates of consciousness by selectively "pushing" an unconscious stimulus into consciousness. (C) 2015 Elsevier Inc. All rights reserved.